12 • 65-2433RK-05 CO Detector
Replacing Components of the CO Detector
This section includes a procedure to replace the CO sensor, the charcoal filter, and the entire detector
assembly. In most cases, it is not necessary to replace the entire detector assembly.
Replacing the Plug-In CO Sensor
CAUTION: The sensor contains electrolyte which is a dilute acid. Do not disassemble the sensor
when replacing it with a new one. If sensor electrolyte comes in contact with your skin,
wash affected area thoroughly with soap and water.
1. Turn off the controller.
2. Turn off or unplug power to the controller.
3. Unscrew the detector housing cap from the detector housing body. Make sure not to lose the cap
gasket.
4. Unplug and remove the CO sensor with the boot and charcoal filter attached.
5. Remove the rubber boot and charcoal filter from the old sensor.
6. Remove the replacement sensor from its packaging and remove the wire jumper. This wire jumper
is installed on the sensor pins for shipment or storage but must be removed for the sensor to
Slow or No
Response/
Difficult or
Unable to
Calibrate
• Unable to
accurately set the
zero or response
reading during
calibration.
• Detector requires
frequent
calibration.
Note: Under
“normal”
circumstances, the
transmitter requires
calibration once
every 3 months.
Some applications
may require a more
frequent calibration
schedule.
• The calibration
cylinder is low, out-
dated, or defective.
• The flame arrestor in
the detector housing
cap is wet or clogged
with dirt or other
particulates.
• The calibration gas
is not an appropriate
concentration.
• The detector is
malfunctioning.
1. Verify that the calibration cylinder
contains an adequate supply of a
fresh test sample.
2. Check the detector housing cap to
determine if the flame arrestor is
wet or dirty. Clean if necessary.
3. Verify that the calibration gas
concentration is appropriate for
the transmitter. Zero emission air
(20.9% oxygen) is normally used
for a zero adjustment if the
environment is suspect and 50
PPM CO in air is normally used
for a response adjustment.
4. If the calibration/response
difficulties continue, replace the
plug-in sensor as described later
in this section.
5. If the calibration/response
difficulties continue, contact RKI
for further instruction.
Unexplaine
d Upscale
Readings or
Alarms
• Controller
indicates a CO
reading that cannot
be verified.
• CO alarms occur at
the controller that
cannot be
explained.
• Charcoal filter is
saturated and no
longer scrubbing out
interfering gases.
1. Replace charcoal filter.
2. If difficulties continue, contact
RKI for further instructions.
Condition Symptom(s) Probable Causes Recommended Action